With the progressive aging of electrical power transmission equipment, growing awareness focuses on the reliability of the equipment. Decisions regarding associated substation equipment refurbishment or replacement, for example, may take into account the need to extract maximum return from operating costs and capital investments. Such decisions may rely on a dependable assessment of equipment. Several methods have been proposed for classifying the condition of certain power transmission components based on limited duration check-up type testing. However, the limited “snapshot” data acquired in such equipment tests may not provide a realistic evaluation of actual equipment conditions. A need remains for improved systems and methods for asset condition monitoring in electrical power substation equipment.